How do I take out the coolant sensor?

[tazman]

Hi, I got a 1991 525i. I am getting low coolant signal when I turn the car on and also when I turn it off. But as soon as I start driving it goes away and does not come back till I turn the car off. I am guessing that may be the magnet or float in the sensor is sticky. I would like to take it out the sensor and clean and see whether I can make it work. Is there an easy way to take the coolant sensor out? I am not good with plumbing. Do I need to take the rad out for this? Is there a way to pop the coolant reservoir or take the sensor out from under the car? If I do take the sensor out does that mean I have to go through the whole process of bleeding the coolant and so on? Just would like to know what’s involved before I get into this. thnx

[Blitzkrieg Bob]

the terminal and plug.

may just be some corrosion and dirt.

[uberkarldrei]

Left front side of car, follow the radiator cap down to the bottom of the expansion tank and you will find a plug with a couple wires. that is the sensor. it is mounted upside down from all the previous years models. yes you will have to drain to remove. all the parts are plastic so if you do be careful with the wrench and don't crack stuff. pull up REALOEM on the web for pictures. for the Kludge method of getting rid of the alarm and visually checking your coolant periodicly, pull the plug that goes into the sensor and bridge the two contacts with a piece of wire. this is not the prefered but you can get your display back on the LED. sorry I don't have any spares to sell as I usually just live with the broken stuff untill I get the parts

[Paul in NZ]

it only displays some warnings at start up and shut down.So i would say replace the sensor or at least pull it out and see if it needs cleaning like Bob says.With an older car the coolant level warning is a good thing to have,so if you develop a leak in the system you do get a warning about it.If the sensor is all dirty and clogged its prolly an indication the cooling system needs flushing and refilling with an appropriate water/anti freeze(read corrsion inhibitor) mixture

[tazman]

thnx bob, paul and all. I took the plug out and shorted with a jumper and the warning goes away. So it is the sensor. I have some question before I take the sensor out and examine. If I take the sensor out does that mean I need to do a coolant flash? I read that the process is a lil hard as you need to bleed the system over and over again. I also notice there is a small leak on the top of my radiator. When the engine is in high rev I can see a lil bit of water droplets trying to come out from the top. It just stay there does not roll down. I have been checking my coolant level every day and I don't see a drop. Can any of you put some pics of the location of all the drain plug and bleeder screw. I am not good with plumbing and would like to get as much info as possible before going down that road. thnx